Looking at the trend Bank Nifty is making continious lower lows from the start of the month & has been halted near 51000 to 51300 sideways from last 4 days. Looks like a move can come if the it breaks range of 51000 or 51300.
Also BN moving downside below daily trend line still hovering at support 51000. if breaks with restest a bearish move is expected.